This album was originally recorded in 1991 and intended to be the first full-length by Fear Factory, but the band wasn't happy with the record deal they were in, so they ditched their producer, then-unknown Ross Robinson. When they were taken to court, that producer won the rights to the album, and the band won the rights to songs. Incidentally, the producer of Concrete ended up using this album to promote himself.

For "Demanufacture":
Echoes of Innocence (as a Therapy for Pain with new lyrics and music)
Piss Christ (as Pisschrist with new lyrics and music)

For "Obsolete":
Concrete (as 'Concreto', first re-recorded for the 'Dog Day Sunrise' single and later ported to "Obsolete" for the digipak; just as bonus track)
Soulwomb (as Soulwound with new lyrics and music; just as bonus track)

For "Cry Now, Cry Later Volume II Compilation":
Sangre de Niños

Every other track not mentioned on this list was never re-recorded and can only be found on this album.